Push-button electric switch



K. C. ALLlSON PUSH-BUTTON ELECTRIC SWITCH Oct. 12, 1954 2 Sheets-Sheet 1Filed March 17, 1949 I r m D 5D Oct. 12, 1954 K. c. ALLISON 2,691,702

PUSH-BUTTON ELECTRIC SWITCH Filed March 17 1949 2 Sheets-Sheet 2 ,2 Q3 II :1)-

INVENTOR.

BY I 62% Patented Oct. 12, 1954 UNITED STATES PATENT OFFICEGrigsby-Allison Company, Inc.,

Arlington Heights, 111., a corporation of Illinois Application March 17,1949, Serial No. 81,860

12 Claims. 1

This invention relates to electric switches of the type featuring anumber of push-button switches and is particularly applicable toswitches for handling complicated circuits in automatic stationselection and other operations in a wireless receiving set,inter-communication systems, automatic coin-operated devices, varioustypes of test equipment and the like.

It is an object of this invention to provide an improved switch of thistype which is simple and inexpensive in construction and design, anddurable and efficient in its operation.

The present invention also provides a multiple push button switchcomprising a frame, an insulated support mounted thereon for slidingstraight line motion relative thereto, a second insulated supportarranged in spaced parallel relation to the path of movement of saidfirst support and fixed on said frame, a series of rigid contacts fixedto said second support, said contacts projecting toward said firstsupport and arranged in spaced apart aligned relation lengthwise of thepath of movement of said first support, and means slidably engageablewith the contacts on said second support including a 2 Fig. 11 is afragmentary vertical sectional view taken on line I ll I of Fig. 10.

contact member carried by said first support and connected thereto forlimited movement relative to said first support.

Further objects of this invention will appear in the following detaileddescription, taken in conjunction with the accompanying drawings,forming a part of this specification, and in which drawings,

Fig. 1 is a top plan view of a switch embodying the present inventionshowing the second insu lated support in fixed relation to the switchframe.

Fig. 2 is an end elevation thereof as viewed from the left side of Fig.1.

Fig. 3 is a rear elevation as viewed from the bottom of Fig. 1.

Fig. 4 is a bottom plan view.

Fig. 5 is similar to Fig. 1 with the second insulated support removed toexpose the details of the push button and the first insulated supportdriven thereby.

Fig. 6, and Figs. 7 and 8, are eachenlarged detail views showing thelocking mechanism in various positions of rotation incident to a cycleof releasing a push button preparatory to further locking thereof ininwardly pushed position as applied to the push button switch appearingat the left hand side of Fig. 4.

Fig. 9 is similar to Fig. 5 with the first insulated support removed.

Fig. 10 is a vertical sectional view taken on line 5 lU-l 0 of Fig. 1.

Fig. 12 is an enlarged fragmentary view, part in section and part inelevation, illustrating the assembly of the first insulated support andthe contact member mounted thereon.

Fig. 13 is similar to Fig. 12 with the parts turned about an uprightaxis through an angle of degrees relative to the position shown in Fig.12.

Fig. 14 and Fig. 15 are top and bottom views of the parts shown in Fig.12.

A multiple switch assembly representing an embodiment of the presentinvention, as shown in the drawings, comprises an insulating panel ll!of Bakelite punching stock or the like, which is arranged across the topor open end of a metal casing of rectangular plan having a bottom wall I1, front and rear end walls [2 and I3, respectively, and opposed sidewalls ['6 and HS extending upwardly from the bottom wall. Lugs 9extending upwardly from the top edges of the walls I4 and i5 penetratethe panel It to provide a rigid attachment thereof to the casing.Mounting of the casing is provided by means of openings provided in thefront wall l2 and in portions of the latter extending longitudinallybeyond the walls M and 15, as well as openings in the bottom wall, saidopenings being designated by the reference numeral 16.

Slots [1 and I8, respectively, formed in spaced relation lengthwise ofthe front and rear walls of the casing provide bearings in which aseries of push rods it are supported in parallel spaced apart relationlengthwise of said walls [2 and [3 for sliding movement in a coplanarpath in downwardly spaced parallel relation to the panel I0. The slots[8 are arranged in pairs for the reception of laterally spaced guidearms 20 at the rearward end of each push rod [9. The slots I! eachaccommodates a reduced stem or handle portion 2'! for operating the pushrod from a convenient position outside the front wall [2. A coil spring22 encircling one of the guide arms 20 bears against the inner surfaceof the rear wall l3 about the slot l8 containing the guide arm of eachplunger or push rod I9 to normally urge the latter toward the front wall[2. A stop 24b on the second guide arm 20 of each push rod (except thepush rod farthest to the left as in Fig. 1) engages the edge of itsbearing slot l8 to limit movement of the push rod in the direction ofthe wall [3 against the pressure of the spring 22. The holes i dobetween the slots I! are preferably formed to create burred edges on theinner surface of the front wall t2. These edges present barbs engageablewith a composite member or strip 23 of metal and felt or other suitablecushioning material with the felt side away from the inner surface ofthe wall I 2. After the push rod is positioned with its stem portionprojecting through the slot l7 and the guide arms subsequently threadedthrough the slots [8 in the rear wall of the casing, the push rod ispushed rearwardly to provide clearance between the shoulder 24 and theinner face of the front wall l2 whereupon the strip 23 is dropped intoplace. Thus the strip 23 acts on the shoulder 24 to maintain the guidearms 29 in outwardly projecting position through the slots [8.

The panel [9 provides a base for a series of spaced apart contactmembers arranged in single or double rows in upwardly aligned relationto the path of movement of the push rods l9. In one form, the contactmembers each includes a blade portion 25 protruding from the lowersurface of the panel l9 and having an integral mounting portionpenetrating openings 26 in the panel H) which terminates in a terminalconnecting portion 2! at a distance above the upper surface of thepanel. The mounting portion is so anchored within the opening 26 as tomaintain a fixed position peripherally of the opening while integralwings 28 formed at the base of the terminal Connecting portion 21 andstaking of the blade portion 25 as at 29 cooperate with the edges of theopening 26 to rigidly secure the blades against displacement verticallyof the opening 25. Thus the faces of the blade portion, as clearly shownin Figs. 10 and 11, are held in coplanar relation to the faces of theblades 25 of the contacts in alignment therewith lengthwise of the pathof movement of the push rod therebelow.

Another type of contact member includes similar blade portions 39 whicheach form the lower end of angularly bent tongues or ears 3| shearedfrom an elongated metal conductor strip 32 arranged across the uppersurface of the panel H], with its longitudinal axis across the paths ofthe push rods [9. The tongues 3i penetrate and are anchored withinopenings 33 similar and at spaced intervals corresponding to thearrangement and spacing of the openings 26, whereby the blade portionsoccupy positions in alignment with and form complements of the rowscontaining the contact blades 25. As illustrated in Fig. -l, the presentswitch includes two such conductor strips 32, each strip having itstongues 3| bent inwardly toward the other strip and arranged to providecontact blades 30 in each strip alternately with the blades 30 of theother strip in alignment with selected rows of contact blades 25. Eachof the conductor strips 32 thus provides a bus bar for a multiple seriesof contact blades 39, and includes a terminal connecting portion at oneend thereof, as indicated at 34. This interconnection of the contactblades 30 affords added resistance to strains applied thereto inconnection with switching operations.

Each of the push rods I9 is adapted to actuate a contact holder or panel35 of insulating material such as the composition of panel [0. The panel35 supports contact members, to be more particularly describedhereinafter, for movement toward and away from bridging engagement withselected blades 25 and 30 in alignment with the path of such push rodand secured to the panel ID as hereinbefore described. Each holder 35has a reduced end portion 38 which has sliding support in a slot 39 inthe rear wall 13 of the casing. A lug 40 formed in and extendingupwardly from the body of each plunger enters a slot 4| provided in theholder 35 whereby the latter is operatively connected with theassociated push rod. An offset 40a formed in the upright edge of thelugs 40 engages the undersurface of the holder 35 about the slot M whichin cooperation with the slot 39 in the rear wall l3 of the casingcontaining the reduced end portion 38 of the holder 35 supports thelatter at a fixed distance below and parallel to the lower extremitiesof the contact blades 25 and 39 attached to the panel Hi. In switcheswherein only a single row of contact blades 25 and 30 are used inconnection with an associated push rod and contact holder 35, unbalancedresistance developed between the stationary and movable contacts tendsto strain the holder 35 about an axis lengthwise of the path of itsmotion under control of the push rod l9. However, the edges of the slot39 in the rear wall l3 of the casing act on the portion of the holder 35extending therethrough to prevent such distortion of the holder.

Referring more particularly to the details of the contact memberscarried by the holder 35, as shown in Figs. l2, l3, and 14, it is to benoted that each such contact member is mounted in an opening 42 in theholder, which opening is of rectangular plan. Opposite edges 43 and 44of the opening 42, which are parallel to the line of motion of theholder, present surfaces engageable by the outer faces of spaced uprightarm or shank portions 45 connected at their lower ends by a bridgeportion 46. Tongues 41 forming lateral extensions of the bridge portion46 are arranged to overlap the edges of the opening 42 on the undersideof the holder 35 whereby the arms 45 are held against upward withdrawalfrom the opening 42. Branching upwardly from each of the arms 45 andspreading in opposite directions there from lengthwise of the line ofmotion of the holder 35 is a contact shoe 48 to provide a pair of shoesadapted to span the length of the space occupied by two neighboringblade portions of the contact members projecting from the top panel l9.Each shoe member has a straight horizontal bottom edge portion 49 whichengages the upper surface of the holder 35, with the opposite endsthereof at a distance apart approximately equal to half the maximumlength of the shoe. A straight edge portion 50 extends upwardly from theend of each bottom edge portion to a height approximately equal toone-half the maximum height of the shoe. The area of the shoe lyingabove said edge 56 is bounded by an edge 5| of circular contour whichterminates in a downwardly offset straight top edge portion 52. A notchor slot 53 intersecting the straight top edge portion 52 centrally ofits length divides the shoe substantially throughout its height to forma pair of separated branches of equal size. This separation affordsindependent resiliency in the branches of each shoe. A circular areabounded by the circular edge 5|, on each of such branches, is preferablyformed to present inwardly facing spherical convex surfaces 54 againstwhich the blades 25 and 30 have wiping engagement.

The distance between the tabs or tongues 41 and the bottom edge portion49 of the contact shoe 48 is slightly greater than the thickness of theholder 35 and that the space between the edges 43 and 44 of the opening42 in the holder is slightly greater than the space required toaccommodate the arms 45. Due to such clearances, the arm portions 45cooperate with the opening 42 so as to furnish limited movement of thecontact shoes 48 relative to the holder for self-align- 5. ment purposeswith the stationary blades 25 and 30.

As shown in Fig. 11, the clearance between the uppermost edge portionsof the contact shoes 48 and the lower surface of the panel lEl is lessthan the clearance between the lower edge of the stationary blades 25and 30 and the upper surface of the holder 35. Under this arrangement,the contact shoes 4-8 are engageable with the surface of the panel ll!to positively maintain the lower edges of the stationary blades 25 and35 out of engagement with the plate or holder 35, thereby avoiding anydistortion or bending of the blades which might develop due to forceapplied by the holder 35 directly to the. free ends of the bladesincident to. switching motions.

As shown in Fig. 9, the push rod positioned farthest to the left. isillustrated in inwardly locked position. This particular push rod isshown as controlled with a latching member 55. which operatesindependently of the latching means controlling the other push rodsdetailed in Fig. 9. The latching member 55 appearing in Fig. i ispivoted as at 550i to the underside of. the push rod [9. A notch at theleading end of the latching member 55 is engaged by a lug 55 formed.integrally with the bottom wall of the casing and projecting upwardlyand forwardly into the path of the member 55 so as to rotate the latterin a clockwise direction as viewed in Fig. 8. The notch at the trailingend of the member 55 is thereby rotated into a position to be obstructedand engaged by a lug or stop. also formed integrally with the bottomwall of the casing. and projecting upwardly therefrom. When sopositioned, the wheel operates to lock the push rod l9 against movementaway from an inward position. Upon inward movement of the push rod fromthis position. the member 55 engages the lug 55 causing the member 55 tomove clockwise a distance suiiicient to move the notch formerly engagedby the lug 51 clear of the lug 51. The member 55 is thus engaged by thelug 57 during movement of the plunger or push rod [5 to an outwardposition toward the front wall i2 whereby the notch at the leading endof the member 55 is prepared for re-engagement with the lug 55 when nextmovement of the push rod I9 to an inward position is brought about. Toenable the push rod l5 to move a sufiicient distance inwardly toaccommodate the travel required by the member 55 between the lugs 55 and55, Without straining the holder 35,. lost motion is afforded betweenthe holder 35 and the push rod lit by elongating the slot. 4| as at Mawhich receives the lug 40; The edges of the member 55 extendinglengthwise of its center line are so formed as to provide 2. lateraloffset. This offset engages the lug 5! so as to stop the rotation of themember 55 while its center line is parallel to the line of motion of thepush rod on which it is mounted. It will be noted that this offsetprojects slightly beyond the lug 51 so as to prevent rotation of themember 55 in a direction counter to the direction which it is intendedto be rotated preparatory to its next succeeding position of lockedengagement with the lug 57. Movement of the push rod carrying the member55 described above is limited in the direction of the lug 56 by a stop24a formed on the arm Ell of the push rod, said stop being engageablewith the edge of the opening 18 in the rear wall l3.

The push rod appearing second from the right hand end of the series ofpush rods shown in Fig. 9, as well as Figs. 1, 4 and 5, is in inwardlylocked position under control of a sliding latch bar 58,

with which the push rods appearing third, fourth and fifth from saidright hand end also cooperates i-nsuch a way that the inward movement ofany one of said push rods automatically releases any other of said pushrods already locked in inward position. The latch bar 58 is arrangedbelow the push rods I9 for sliding movement on spaced proiectionsiformedin and extending upwardly from the bottom wall of the casing. One endthereof slides in a recessin an upright member 59 formed integrally withthe bottom wall of the casing while the opposite end,.consisting oflaterally spaced prongs 55 and 51 have sliding support in notches orrecesses formed in the end wall l5 appearing at the right hand end ofthe unit as viewed in Fig. 9. A coil spring 62 encircling the prong 6iand a section 53 of the bottom wall of the casing acts against the latchbar 58 and. the inner surface of the wall i5 to urge the bar in adirection away from the wall. A locking shoulder 54 is formed on onelongitudinal edge of each of the push rods numbered two, three, four andfive from the right hand end of the unit as viewed in Fig. 9. The edgeportion of each push rod iii in trailing relation to the locking.shoulder 55 according to movement of. the rod into inward position, isbeveled laterally outwardly from the inner limits of the lockingshoulder, as at 55. Upstanding ears 56 on the latch bar 58 are arrangedin alignment with the line of motion of the push rods so as to engagethe shoulder (it of a selected rod and hold such rod in inwardly movedposition, as will be more apparent from the position of the secondplunger from the right as viewed in Fig. 9. Accordingly, upon movementof either of the plungers appearing asthird, fourth or fifth from theright in Fig. 9, the car 55 inthe path of said push rod will be cammedto the right by the bevelled edge 55. thereof so as to release theformerly locked push rod for movement out of inward position. Thereuponthe shoulder 55 of the rod which operated to release the formerly lockedpush rod will be engaged by the ear 55 of the latch bar 58 to thereafterhold such inwardly moved push rod in locked condition.

The push rod positioned farthest to the right in Fig. 9 is provided witha bevelled edge portion 5? cooperating with an upstanding ear 68 at theend of the latch bar 55 whereby inward movement of this rod by thelatter operates to release any other push rod adapted to be held inlocked position by the latch bar but is not itself held in inwardlylocked position by such latch bar.

What is claimed is:

1. An electric switch comprising a frame, an insulated supportmountedthereon for sliding straight line motion relative thereto, asecond insulated support arranged in spaced parallel r lation to thepath of movement of said first support and fixed on said frame, a seriesof rigid contacts fixed to said second support, said contacts projectingtoward said first support and arranged in spaced apart aligned relationlengthwise of the path of movement of said first support, and meansslidably engage-able with the contacts on said second support includinga contact member carried by said first support and connected thereto forlimited movement relative to said first support about an axis lengthwiseof the path of movement thereof.

2. An electric switch as defined in claim '1 wherein said contact memberconnected to the first support is simultaneously engageable with twoneighboring contacts on said second support 7 in one position ofmovement of said first support.

3. An electric switch as defined in claim 1 wherein said contactconnected to the first support is movable about an upright axis.

4. An electric switch as defined in claim 1 wherein said contact memberconnected to the first support is simultaneously engageable with a pairof the contacts on said second support in one position of movement ofsaid first support, and said contact member is divided by a slotextending downwardly from its upper edge substantially midway of itsdimension lengthwise of the line of motion of the first support.

5. An electric switch as defined in claim 1 wherein said contact memberconnected to the first support comprises a shank portion consisting ofspaced arms projecting through an opening formed in the first support,and integral portions branching upwardly therefrom and extending inopposite directions lengthwise of the line of motion of the firstsupport.

6. An electric switch as defined in claim 1 wherein the first support isprovided with an opening therethrough, and said contact member isconnected thereto by spaced arms on said contact member projectingthrough said opening, and said contact member is retained againstwithdrawal therefrom by means of tongues formed integrally with aconnecting portion at the lower ends of said spaced arms and engagingthe bottom surface of the support aforesaid.

7. An electric switch as defined in claim 1 wherein the contact memberconnected to the first support comprises a pair of shoes presentinginwardly facing surfaces with which the contacts on the second supporthave sliding engagement, and said inwardly facing surfaces are formedwith inwardly facing spherical convex areas thereon.

8. An electric switch as defined in claim 1 wherein said contact membercarried by said first support presents edge portions engageable with thesurface of said second support to maintain said first support at adistance clear of the contacts on said second supports.

9. An electric switch comprising a frame, a series of independentinsulated supports mounted on said frame for sliding straight linemotion relative to said frame in a common plane, a second insulatedsupport arranged opposite and parallel to the paths of said firstsupports and fixed on said frame, a conductive strip arranged on thesurface of said second insulated support having integral portionspenetrating said second insulated support to provide a blade portionwhich projects downwardly from said second insulated support, a seriesof contacts projecting toward first supports and together with saidblade portion on the conductive strip are arranged in spaced apartaligned relation lengthwise of the path of motion of said firstsupports, and a contact member on each of said first supports slidablyengageable with said blade portion on the conductive strip and thecontacts on said second support in alignment therewith lengthwise of theline of motion of said first supports.

10. In an electric switch the combination of a frame and an insulatedsupport mounted on said frame for sliding straight line motion relativeto said frame, said support presenting opposed flat surfaces, eachparallel with the other, lengthwise of its line of motion, a slot formed-in said support penetrating said opposed surfaces, said slot havingopposed parallel edge portions lengthwise of the line of motion of thesupport, a contact member comprising spaced apart parallel armsprojecting through said slot, a connecting portion at one end of saidarms having integral tongues extending therefrom in opposite directionslengthwise of the line of motion of the support engageable with thesurface of the support about said slot, a contact shoe branchingupwardly from each of said arms and spreading in opposite directionslengthwise of the line of motion of the support beyond opposite edgeportions of said slot, the distance between said tongues and the contactshoes being slightly greater than the distance between the faces of saidsupport whereby said contact member has limited movement relative tosaid support.

'11. In an electric switch as defined in claim 10 wherein each contactshoe is divided substantially centrally of its dimension lengthwise ofthe line of motion of the support.

12. In an electric switch as defined in claim 10 wherein each contactshoe has a straight bottom edge engageable with the surface of thesupport with the ends thereof at a distance apart approximately equal tohalf the maximum length of the shoe, each bottom edge thereuponextending upwardly and outwardly to a height approximately equal toone-half the maximum height of the shoe, and the area of the shoe lyingabove said slanting edge being bounded by an edge of circular contour.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,146,269 Puerner Feb. 3, 1939 2,196,433 Allison Apr. 9, 19402,213,845 Mastney Sept. 3, 1940 2,234,405 Hall et al. Mar. 11, 19412,441,614 Baumer May 18, 1948 FOREIGN PATENTS Number Country Date517,202 Great Britain Jan. 23, 1940 517,898 Great Britain Sept. 13, 1945673,390 Great Britain June 4, 1952

